Easels of the tripod style have been available for many years for use in displaying works of art, charts, posters and the like, as well as serving as working easels for artists. All such easels are of the same basic design, having legs joined at the top with a rear leg hingedly mounted relative to the others so that it can be shifted between a retracted position adjacent to the plane of the other two legs and an angularly extended position in which the three legs form a triangular support for the art work. In this type of easel, the two front legs are generally joined by a tray which supports the art work while the third leg is relatively movable from the retracted or storage position to the extended position for use.
A major draw back of this design is that the rear leg is attached only at the top, and this arrangement allows for a great deal of motion that compromises the stability of the easel. For example, pushing the easel backwards may cause the rear leg to fold inwardly causing a collapse. In addition, the weight of the art work or downward pressure may cause the rear leg to slide backwards, also resulting in collapse. To counteract this, most easels have a chain or chains attached to the rear leg and the front tray to prevent the rear leg from sliding back too far. This still leaves the easel unstable with the rear leg vulnerable to lateral movement or, if the easel is pushed, to movement toward the front legs. It also makes the easel, which is meant to be portable, awkward to move since the rear leg will swing around during transport.
Various ways of stabilizing the rear leg have been adopted in the past. Known means involve use of rigid metal braces which permanently lock the legs in place. Sometimes metal braces hinged in the middle and being lockable in the straight position to fix the legs in position have been employed. Relatively slidable pieces fixed to the legs are provided with fasteners which allow for interlocking the pieces in a plurality of positions to selectively lock the legs in the extended or retracted positions. Each of the known alternatives is relatively expensive, and as a result, none of them have been widely adopted. As a result, a long-felt need has persisted for a universally acceptable stabilizing device which is simple to manufacture, made from readily available and standard materials and which can be fit to almost any tripod easel. Such a device should be inexpensive and easy for the average consumer to install on previously purchased easels.